Method of producing propping agent



May 1967 c. F. LANG ETAL METHOD OF PRODUCING PROPPING AGENT Original Filed Dec. 1, 1960 INVENTORS CHARLES F. LANG JOSEPH E RITTER VERNON D. CLAIBORNE ATTORNEYS.

United States Patent Office 3,316,748 Patented May 2, 1967 '7 Claims. 01. 72-377 This application is a division of Ser. No. 73,098, filed Dec. 1, 1960, and now abandoned.

This invention relates to system for increasing the yield of underground formations such as oil wells. More particularly, this invention concerns aluminum particles of appropriate size and strength to be readily injected into underground fractures for holding the fractures open to increase the permeability of the well to fluids, whereby the yield is increased. The invention further provides apparatus and method for producing these aluminum particles.

Others have disclosed the advantages in the use of spheroidal aluminum particles for propping open the fractures in oil wells to increase the permeability of the well and hence the yield from the well. The present invention provides improved aluminum particles for such use, and the means and method of producing them. The aluminum particles of the invention have improved hardness and strength, and appropriate size, so as to be readily injected into the fractures and to sustain the heavy loads produced by the earth formations, thereby maintaining the fractures open.

According to the invention, apparatus is provided for increasing the hardness and strength of cast aluminum particles or shot so as to make the particles appropriate for use as propping agents.

The invention also provides a method for increasing the hardness and strength of the particles by producing repeated dynamic loading on the particles. By a plurality of impacts wherein the particles are impinged upon reaction surfaces, work-hardening and shaping of the particles are produced.

The modified particles are generally spherical in shape and have a plurality of work-hardened facets produced by the impacts. The modified particles have superior strength, corrosion resistance and physical uniformity. Further, the central portion of each particle is preserved in a relatively resilient form, whereby cracking or splitting under compressive loads is resisted.

For a better understanding of the invention and its other objects, advantages and details, reference is now made to the presently preferred embodiments of the invention which are shown for purposes of illustration only, in the accompanying drawings.

In the drawings:

FIGURE 1 is an enlarged semi-diagrammatic view of a modified aluminum particle or pellet according to the invention, having a plurality of work-hardened facets thereon;

FIGURE 2 is a front elevation of apparatus for modifying cast particles to produce the pellets of FIGURE 1;

FIGURE 3 is an end elevation of the apparatus shown in FIGURE 2; and

FIGURE 4 is a vertical section taken along the line 44 in FIGURE 2.

The term aluminum particle, as used herein, means a particle having aluminum as its major component and includes particles formed of pure aluminum and of aluminum alloys.

Initially, aluminum particles are formed as by centrifugal casting, employing a rotating melt of aluminum or aluminum alloy which is centrifugally passed through holes in a perforated tube or pot. The particles are centrifugally hurled either into air or Water where they solidify into pellets or particles.

Next, the cast particles are modified employing the apparatus 10 shown in FIGURES 2 to 4 to produce particles as illustrated in FIGURE 1. The cast particles are introduced into axial inlet 12 opening into the upper housing 14 of the modifying apparatus 10. The particles are moved by the action of rotor or fan blades 16 secure-d to drive shaft 18 rotated by a power source (not shown). The blades 16 hurl the particles 19 against the surfaces 20 of angle members 22 secured to the inner surface of the housing 14. The dynamic loading produced by the contact between the blades 16 and the particles 19' and between the surfaces 20 and the particles 19 produces a work hardening of the metal and converts the shape of the particles to generally spherical.

The particles 19 gradually pass or trickle through the throat 24 connecting the interior of the upper housing 1'4 with the interior of lower housing 26. This lower housing is provided with rotor or fan blades 30 fast to drive shaft 32 driven by a power source (not shown). Angle members 34 are secured to the inner surface of housing 26 to provide reaction surfaces 36 for impingement by the aluminum particles. The reaction surfaces 20 and 36 extend obliquely to the radii of the housings so as to be substantially perpendicular to the path of particles 19 impelled by the blades. Further Work hardening and rounding of the particles is produced by the dynamic loading on the particles 15 occurring within housing 26. The modified particles leave by the tapered discharge outlet 49 and have the general appearance of that shown in FIGURE 1.

The housings 14 and 26 are connected to a plate 42 fixed to a base 44. Each modified particle 19 has a plurality of substantially fiat, work-hardened facets 41.

Whenever the provided adjustability of throat 24 is not sufiicient to yield an adequate retention time in the modifying apparatus, the particles may be recycled. However, a more efficient production system is achieved by use of a plurality of devices 10, connected in tandem.

In such an arrangement, the output of one apparatus 10 is connected to the inlet of another similar apparatus, in order to achieve the desired total retention time.

The modification of the particles by dynamic loading or impact loading produces a general uniformity of the size of the particles. This has been found to be important in the use of the particles as propping agents in oil wells. The uniformity of the size becomes important when the particles are distributed in generally a single layer across the area of a fracture in the earth. When the particles are of substantially the same size, they tend to each bear a portion of the load so that the load is distributed among the various particles and not concentrated on a few of the particles.

Following are examples of the operation of the apparatus of the invention in modifying various samples of aluminum particles. The conditions of operation have been tabulated. The analysis of the particle sizes and distribution of sizes of the particles is tabulated, according to sieve screen sizes, both before and after modification by apparatus 10. The fractions of the particle mixtures are indicated by mesh sizes employing the minus and plus signs. The minus sign indicates the limiting screen, which is the screen through which all the particles of the fraction pass. The plus sign indicates the retaining screen, which is the screen on which all the particles are retained.

In the examples, under mesh size, the percents by weight of each fraction or portion of the particle mixture are listed for sieve size limits. Thus, in Example I, opposite pass 1, +8=75% means that 75% by weight of the sample is retained on a sieve of mesh size 8. Further, 8+10=2l.0% means that 21.0% by weight of this sample of particles passes through a sieve or screen of mesh size 8 and is retained on a sieve of mesh size 10.

The testing sieves or screens employed are of the U.S. Sieve Series, U.S. Bureau of Standards, Standard Screen Series of 1919, wherein mesh sizes correspond to apertures as follows. The aperture is the minimum clear distance between the edges of the opening in the screening surface:

A Mesh number: Aperture in inches 6 0.132 8 0.0937 10 0.0787 12 0.0661 16 0.0469 20 0.0331 0.0232 0.0155 0.0117 0.0098

In the examples, Discharge Opening Size, Top Unit, is the area of throat 24, as seen in FIGURE 4. Similarly, Discharge Opening Size, Bottom Unit, is the minimum area of outlet 40, as seen in FIGURE 2. Weight of mixture is the weight of aluminum particles in the sample. Processing time is the duration during which the sample remains in modifying apparatus 10. Condition describes the hardness and uniformity of the modified particles. Fan Speed is the speed of drive shafts 18 and 32 and revolutions per minute. Passes indicates each passage of the sample successively through apparatus 10. That is, in Example I, the sample of particles was passed only once through apparatus 10. But in Example III, the sample of particles was passed three times through the apparatus 10.

In Examples I to IX, the particles employed were aluminum alloy designated 1100, containing at least 99.00 percent by weight of aluminum.

Initial Modified Analysis Analysis Discharge Opening Weight 0! Fan Example Passes Size Sample and Condition Speed, Processing Time r.p.m. Mesh Size Mesh Size -8 +10=2l. 0 8 +10 13. 0 x 9" top unit 49 lb./14% min. 10 +12= 4.0 10 +12 0.5 1" x 9 bottom unit 2041b./hour Good 2,000 I II 1 +8=69. 5% 1" x 9" top unit 491b./7 min.

-8 +10=25. 5 1% x 9" bottom unit 420 lb./h0ur Fair 2, 000 10 +12= 5. 0 2 +8=92. 5% 1" x 9 top unit 481b./7 min.

-8 +10= 7. 5 1%" x 9" bottom unit 410 lb./hour Good 2, 000

III 1 +8=77. 0%

8 +10=19. 0 1%" x 9 top unit 49 bl./10 min. 10 +12= 2. 5 2" x 9" bottom unit 294 lb./hour Poor 2,000 -12 +16= 1. 5 2 +8=95. 0% 1%" x 9 top unit 481b./6 min.

8 +10- 5.0 2 x 9 bottom unit 480 lb./hour Fair 2, 000 3 +8 96. 5 1%" x 9" top unit 471b./4 mm 8 +10 8. 5 2 x 9 bottom unit 7051b./hour Good 2,000

8 +10= 1. 5 10 +12=12. 5 x 9 top unit 49 lb./11% min. Fair 2, 000 12 +16=74. 0 1" x 9 bottom unit 255 lb./hour -16 +20=1l. 5 20 +30= 5 -30=0 .0 2 +8 0. 0%

8 +10 6. 0 10 +12 22. 5 x 9" top unit 48 lb./10% min. Good 2, 000 -12 +16 69.0 1" x 9" bottom unit 2811b./hour 16 +20 2. 5 20 0. 0

13112118 I 1 x 9" top unit 49 lb./6 min. Fair 2, 000 -12 +16=50. 5 1%" x 9 bottom 490 lb./h0ur 16 +20=10. 5 unit 20 +30= .5 30= 0. 0

2 +8= 0.0% -8 +10=13. 0 10 +12=30. 0 1 x 9" top unit 48 lb./6 min. Fair 2,000 -12 +16=54. 5 1% x 9" bottom unit 4801b./hour -16 +20= 1.5 20 +30= 1.0 3 s 1( 1 8 1" 9" 2. x top unit 471b./13 min. Good 2,000 10 +12=26. 0 1% x 9 bottom unit 217 lb./hour -12 +1g=620 0. 0

Initial Modified Analysis Analysis Discharge Opening Weight of Fan Example Passes Size Sample and Condition Speed, Processing Time r.p.m. Mesh Size Mesh Size 8 +10=11. 10 +12=24. 0 1% x 9" top unit 491b./6 min. Poor 2, 000 12 +16=54. 0 2 x 9 bottom unit 4901b./hour -16 +20=10. 0 20 +30: 1. 0 30= 0.0 2 1% x 9" top unit 48 lb./4 min. Fair 2, 00

2 x 9 bottom unit 5761b./hour 3 +8= 0.0%

8 +10= 9.0 10 +l2=21. 0 1% x 9 top unit 471b./ min. Good 2, 000 -12 +16=66. 5 2 x 9 bottom unit 534 lb./hour -16 +20: 1. 5 -20 +30= 2 0 30= 0 0 VII 1 0.0%

8 +l0= 3.5 +12=16. 5 1% x 9" top unit 49 1b.]? min Poor 1, 000 -12 +16=69. 5 2 x 9" bottom unit 4201b./h0ur 16 9. 5 20 1.0 30= 0.0 2 1% x 9 top unit 48 1b.]? min Poor 1, 000

2 x 9 bottom unit 410 lb./hour 3 1% x 9 top unit. 47 lb./8 min Poor 1, 000

2" x 9 bottom unit 353 lb./hour 4 +8= 0.0%

8 +10= .5 10 +12=14. 0 1% x 9 top unit 46 lb./8 min Poor 1,000 12 +16=75. 5 2" x 9 bottom unit 345 lb./hour 16 +20=10. 0 I

20= 0.0 5 1% x 9 top unit lb./8 min. Poor 1,000

2 x 9 bottom unit 338 lb./hour 6 1% x 9 top unit 44 lb./7 min. Fair 1,000

2 x 9" bottom unit 377 lbJhour 7 1% x 9" top um't 431b./8 min. Fair 1,000

2 x 9 bottom unit 323 lb./l1our 8 +8= 0 0 8 +10=12 0 -10 +l2=19. 0 1%" X 9" top unit 42 b1./9 min. Good 1,000 12 +16=63. 0 2" x 9 bottom unit 280 lbJhour 16 +20= 6 0 20= 0 0 VIII 1 +8=0. 0%

8 +10=6. 5 10 +12=18. 5 1% x 9" top unit 49 1b./5 min. Fail 3, 000 12 +16=66. 0 2" x 9 bottom unit 588 lb./hour 16 +20= 9.0 20= 0.0 2 +8= 0.0%

8 +10=13. 0 -10 +12=20. 5 1% x 9 top unit 48 lb./3 min. Fair 3, 000 l2 +16=62. 5 2" x 9" bottom unit 9601b./l1our 16 +20= 4.0 20= 0. 0 3 +8= 0.0 r 8 +10= 12. 5 10 +12=18. 5 1% x 9 top unit 47 lb./3% min. Good 3, 000 12 +16=65.0 2" x 9 bottom unit 8061b./hour -16 +2g= 0 2 .0

The following examples relate to modification of aluminum particles of 1100 designation alloy. As cast,

the particles are generally acicular or needle-shaped.

Initial Modified Analysis Analysis Discharge Opening Weight of Fan Example Passes Size Sample and Condition Speed, Processing Time r.p.m.

Mesh Size Mesh Size IX 1 +8= .O%

--8 +12= 0 l2 +16= 5 x 9 top unit 49 lb./9 min. Poor 2, 000 -16 +gg=3g O 1 x 9 bottom unit 326 lb./hour 20 =5 .0

30= 7. 5 2 x 9 top unit 48 lb./8% min. Poor 2, 000

1 x 9 bottom unit 348 lb./hour 3 x 9 top unit 47 lit/13% min. Poor 2, 000 4 8 +12 0 O7 1 x 9 bottom unit 213 lb./hour 0 12 +16- 1.0 16 +20=70. 0 x 9 top unit 46 lb./11% min. Poor 2, 000 20 +0=19.8 1 x 9' bottom unit 240 lb./hour 0= 0. 5 x 9 top unit 45 Dot/11% min. Fair 2, 000

1" x 9 bottom unit 240 lb./hour 6 x 9 top unit 44 lb./11 min. Fair 2, 000

+8 0 1" x 9 bottom unit lb./hour 7 8 +12: 0.0 12 +16= .0 x 9 top unit 4310/1234 min. Good 2, 000 ;g igg=7tig 1 x 9 bottom unit 351 lbJhour 15.

Initial Modified Analysis Analysis Discharge Opening Weight of Fan Example Passes Size Sample and Condition Speed, M h s M h S Processing Time r.p.m.

es ize es rze 12 +16= 2. 0 -16 +20=38. 1" x 9 top unit 49 lb./9 min. Poor 2, 000 20 +30=53. (5) 1% X 9" bottom unit 326 lbJhour -30= 6. 2 1" x 9" top unit 48 lb./3 min. Poor 2, 000

1% x 9 bottom unit 900 lb./hour 3 1 x 9" top unit 47 lb./7 min. Poor 2, 000

1% x 9 bottom unit 403 lb./hour 4 1" x 9 top unit 46 lb./14 min. Poor 2, 000

8 +12 0 7 1%" x 9 bottom unit 197lb./11our 5 0 -l2 +16=10. 5 0 1 X 9 top unit 45 lb.l14 min. Fair 2, 000 1g +2g=68.g 1% x 9 bottom unit 192 lb./l1our --2 +3 =21.

1" x 9 top unit 441b./ min. Fair 2,000 6 1% X 9" bottom unit 264 lb./hour 7 1 X 9 top unit 43 lb./6 min. Fair 2,000

1% x 9" bottom unit 430 bl./l1our 8 1 x 9 top unit 421b./3 min. Fair-Good 2,000 9 8 +12 0 1% x 9 bottom unit 840 lb./l1our Q 12 +16 9. 5 1 x 9" top unit 411b./9 min. Good 2000 %8 5 1% x 9 bottom unit 273lb./l1our 0 30= 0. 0

XI 1 -s +16= 0. 0%

-16 +20=37. 0 1% x 9 top unit 40 lb./9 mm. Poor 2, 000 20 +=57. 0 2 x 9 bottom unit 326 lb./h0ur -30= 6.0 2 1% x 9 top unit 48 lb./0 min. Poor 2, 000

2" x 9 bottom unit 480 lb./hour 3 1%" x 9" top unit 47 lb./6 min. Poor 2, 000 4 8 +12 0 07 2 x 9 bottom unit 470 lb./h0ur 0 -12 +16= 6.0 16 +20=54. 5 1 x 9 top unit 46 lb./7 min. Poor 2, 000 20 +gg=37g 2" x 9 bottom unit 394 lb./hour 2 5 1% x 9" top unit 4511:.(4 min. Poor 2,000

2 x 9 bottom unit 675 lb./hour 6 1% x 9 top unit 441b./6 min. Poor 2,000

2" x 9 bottom unit 440 lb./hour 7 1% x 9 top unit 4311).]6 min. Fair 2, 000

2 x 9 bottom unit 4301b./hour 8 1% x 9" top unit 42 lb./5 min. Fair 2,000

2 x 9 bottom unit 5041b./hour 9 1% x 9 top unit 41 lb./5 min. Fair-good 2, 000

8 +12 0 0 2 x 9 bottom unit 492 lb./hour 10 12 +16=12. 5 1% x 9" top unit lb./6 min. Good 2, 000 6 3 2" x 9" bottom unit 400 lb./hour 0 =1 The invention has also been applied to aluminum TABLE powder of even greater fineness than the previous examples. After seven passes through the apparatus of Knoop Hardness Number the invention, aluminum powder was modified having Alloy the following initial and modified screen size distribution: AS Cast Modified 1- 6061 air cast 54. 71 93. 07 Analysls Modlfied 6061: solution heat-treated for 2 01. 7 102.8

gours at and aged for 8 ours at 5 Mesh Mesh 6061, aged for 8 hours at 350 F-.. 71.85 102. a 25? 2 2i 2 3% so ution ea trea e or 1. 0. jig: 8 $2: 8 hdurs at 070 F. and aged for 8 -10 +12 '5 -12 +16 13' 0 at 0 I 6063, aged for 8 hours at 350 F 56.02 82. 22 5 I 0 5052, air cast 53. 86 79. 90 5 o 3003, water cast. 45.86 68. 43 5 T 1100, air cast 29. 46 44. 57 1100 +1 0 magnesium water cast 43. 40 67. 54 1100 +2% magnesium water cast- 46. 19 69. 1100 +3% magnesium water cast 47. 73 77. 68 Further to illustrate the invention, following is a 388 $253533: $322; 322%- g3 3g 32- 8% table of microhardness of aluminum particles before and after treatment according to the invention. In the column under As Cast, are listed the Knoop Hardness Numbers, when measured with a one kilogram load, for the aluminum particles before modification according to the invention. In the column under Modified, are listed the Knoop Hardness Numbers, when measured with a one kilogram load, of the aluminum particles after modification according to the invention in apparatus 10; it can be seen that these values are at least 40. Under Alloy are listed the alloy designations by theA-digit code of the Aluminum Association:

v vention is forced into the fracture .to. deposit the propping agent therein. This second fluid can be an unmodified crude oil or water, as in the first step, if sufiicient pumping capacity is available.

The modified aluminum particles used as well propping agents should be larger than about 60 mesh and preferably within the screen size range to +20. That is, the particles preferably should all pass through a number 5 mesh screen and be retained on a number 20 mesh screen.

In order that most of the particles carry loads in the well fracture, the sizes of the particles should be generally uniform. Most preferably, an aluminum particle mixture for use as a well propping agent should have a Limiting Screen and a Retaining Screen with mesh numbers differing by not more than 4. The use of aluminum particle mixtures of 12+16 mesh sizing is recommended. The particular sizing employed will depend upon the nature of the underground formation.

Thus it will be seen that the invention provides method and apparatus for producing aluminum particles having strength, hardness, uniformity of size and corrosion resistance for use as propping agents in underground wells.

For additional details concerning the preparation of cast particles which are especially suitable for use in the present invention, reference is made to application Ser. No. 27,961 filed May 9, 1960, by Leland R. Payton, now Patent No. 2,994,102 and Ser. No. 754,014 filed Aug. 8, 1958 by Vernon D. Claiborne and Leland R. Payton, now abandoned.

While presently preferred embodiments of the invention have been illustrated and described, it will be recog nized that the invention can be otherwise variously embodied and practiced within the scope of the following claims.

We claim:

1. A method of faceting, rounding, and work-hardening a cast aluminum particle, said method comprising the steps of: disposing said particle in the path of radially extending rotary blades terminating proximate to a reaction surface whose major portion is spaced from said path by a distance exceeding the width of said particle, striking said particle with a said blade, allowing said particle, as a result of the force of its impact with said blade, to travel freely away from the point of said impact until said particle impinges against said reaction surface, and rebounding said particle off said reaction surface back into said path.

2. The method of claim 1 wherein said particle impacts said reaction surface from a substantially perpendicular direction.

3. A method of producing a work-hardened, substantially rounded, faceted aluminum particle suitable for propping a fracture in a sub-surface earth formation, said method comprising the steps of: rotating a rotor disposed Within a reaction zone defined by a closed reaction surface, said rotor having radially extending blades with side surfaces and with ends terminating proximate to said reaction surface; introducing an aluminum particle in the as-cast condition to said reaction zone in the path of said blade side surface; and, repeatedly, striking said particle with a said blade side surface, allowing said particle, as a result of the force of its impact with said blade side surface, to travel freely away from the point of said impact until said particle impinges against said reaction surface, and rebounding said particle from said reaction surface freely back into the path of a said blade side surface; so that the repeated impacts between said blade side surface and said particle and between said particle and said reaction surface facets and work-hardens the exterior portion of said particle.

4. The method of claim 3 wherein said work-hardened particle has a Knoop hardness number of at least 40 when measured with -a one kilogram load.

5. A method of producing an aluminum particle suitable for propping a fracture in a sub-surface earth formation, said method comprising the steps of: providing an aluminum particle in the as-cast condition, disposing said particle in the path of radially extending rotary blades with side surfaces and with ends terminating proximate to a reaction surface, striking said particle with a said blade side surface, impelling said particle freely away from said blade side surface, and rebounding said particle off said reaction surface and back into said path, thereby deforming and work-hardening only the exterior portion of said particle and preserving the central portion of said particle in relatively resilient form.

6. The method of claim 5 wherein repeated impacts of said particle with said blade side surfaces and with said reaction surface facets, rounds, and work-hardens said particle.

7. The method of claim 5 wherein said particle is impelled substantially perpendicularly against said reaction surface.

References (Iited by the Examiner UNITED STATES PATENTS 406,136 7/ 1889 Hempel 241-43 996,573 6/1911 Eveland 781 2,758,360 8/ 1956 Shetler 291.22 2,816,466 12/ 1957 Gladfelter 7 8-1 2,946,115 3/ 1960 Firm 29-184.4 2,963,772 12/ 1960 Niles 29148.4 3,150,838 9/1964 Adams 211-275 FOREIGN PATENTS 592,414 8/ 1925 France.

CHARLES W. LANHAM, Primary Examiner. G. P. CROSBY, Examiner. 

1. A METHOD OF FACETING, ROUNDING, AND WORK-HARDENING A CAST ALUMINUM PARTICLE, SAID METHOD COMPRISING THE STEPS OF: DISPOSING SAID PARTICLES IN THE PATH OF RADIALLY EXTENDING ROTARY BLADES TERMINATING PROXIMATE TO A REACTION SURFACE WHOSW MAJOR PORTION IS SPACED FROM SAID PATH BY A DISTANCE EXCEEDING THE WIDTH OF SAID PARTICLE, STRIKING SAID PARTICLE WITH A SAID BLADE, ALLOWING SAID PARTICLE, AS A RESULT OF THE FORCE OF ITS IMPACT WITH SAID BLADE, TO TRAVEL FREELY AWAY FROM THE POINT OF SAID IMPACT UNTIL SAID PARTICLE IMPINGES AGAINST SAID REACTION SURFACE, AND REBOUNDING SAID PARTICLE OFF SAID REACTION SURFACE BACK INTO SAID PATH. 